A defined, position in the context of the invention means any position in which the patient is to remain during transport, treatment or the in-patient rest phase. Preferred positions are thus the lying and seated positions, but in principle all other positions are possible to fulfill the respective purpose.
The positioning of patients, both over relatively short periods, for example during transportation in an ambulance, and over relatively long periods, for example during the patient's stay in hospital, is an important factor for a successful treatment.
Gentle positioning of the patient is necessary in particular if problems may occur as a result of the development of pressure sores. The development of pressure sores on exposed body parts (decubitus) generally results in extended stays in hospital and increased treatment costs associated therewith. The problems of the continuous positioning of patients result from the inability of the skin to adapt to the continuous contact with the contact surface. The pressures, shear forces or moisture acting on the skin at specific points damage the skin directly or indirectly. Supply vessels are closed off by external pressure and capillaries are displaced by shear forces, and this may result in undersupplying and ultimately in these skin areas dying out. In addition, the epidermis is softened under the effect of heat and sweat, thus promoting infections.
Placement of the patient in a defined position is, again, crucial for specific treatment methods such as, for example, in modern respiratory therapies. The placement of patients in a defined position is necessary, for example, in the event of burns, injuries of the vertebral column or in respiratory therapies using a rotation bed. Fixing of the body is also necessary in the case of body positions differing from the simple back or stomach position, i.e. in positions which are not neutral with respect to the body's centre of gravity. In addition to the problem of precise therapeutic positioning, there is the further difficulty of the increase in pressure, accompanying any change in position, in the lowermost dependent body parts, with the above-described negative repercussions.
Conventional systems for fixing patients in a defined position, such as, for example, vacuum mattresses, are not suitable, for the reasons described above, for continuous positioning of the patient. Instead, vacuum mattresses are used only for short-term transportation or during an operation.
WO 2005/094369 A2 discloses a method and a device for controlling at least one ventilation parameter of an artificial ventilator for ventilating the lung of the patient in accordance with a plurality of lung positions. The various lung positions are facilitated by using a rotation bed. The patient is fixed on the rotation bed and therefore held in a defined position. One drawback, however, is the fact that gentle positioning of the patient is not facilitated.
A. Paul: More than just pressure reduction—Support surface MiS Activ, Völker World, Issue 17, 2005, pages 7-10, discloses a microstimulation system in which the slatted grid of a conventional mattress was replaced by carrier profiles with active movement elements. The movement elements are controlled by a control unit so that different movement forms on the basis of the so-called basal stimulation can be applied to the patient lying on the mattress. Examples of movement patterns are the “wave”, “rotation” or “angled plane”. In the “wave” pattern, the movement elements to the right and left of the mattress are activated in parallel. The stimulation pattern resembles a wave running through the bed and gives the patient a perception of movement from head to foot. In the “rotation” pattern, the movement elements right and left are activated in an offset manner. Wave peaks in opposite directions arise which correspond to a rotation. After three cycles, the direction of rotation is reversed. In the “angled plane” pattern, all movement elements of one side are activated simultaneously and thus generate this angled plane. After a selection from three prespecified time intervals, the tilt angle changes to the other side.
One disadvantage of this placement system is the fact that there is no precise fixing facility for the patient to hold the patient in a defined position. Thus in total only movement strokes of a few centimeters are possible. A greater tilt of the mattress could not be considered, in order for example to activate certain lung areas of the patient in a targeted manner.
It is therefore an object of the invention to provide a device for the positioning of patients both allowing gentle positioning and at the same time holding the patient in a defined position. This object is achieved by the device according to claim 1 and the method according to claim 10.
The device according to the invention for the gentle placement of a patient or of a body part of a patient in a defined position comprises a mattress having a surface able to adopt a flexible state, as a result of being subjected to a first control signal, and a rigid state, as a result of being subjected to a second control signal, a cushion which is filled with a fluid, rests on the mattress and comprises a flexible wall in the region of the patient or the body part of the patient resting on the cushion, and a fluid pump which is connected via a valve to the fluid in the cushion and via which the internal pressure and/or the internal volume of the cushion may be adjusted to a predetermined value.